1. Field of the Invention
This invention relates to an finisher connected to an image forming apparatus such as a copying machine or a printer and adapted to serve the purpose of, for example, bundling and stapling a plurality of copied or printed sheets, automatically encasing the stapled bundles of sheets with a cover specially designed for enclosure and binding a book.
2. Description of the Related Art
In recent years, as to what is called OA apparatuses, the improvement of each category of performance, such as enlargement of the capacity and reduction of the processing time, has been accomplished for efficient office use.
Among these OA apparatuses, the copying machine has already arrived at maturity in respect of basic performance. Recently, while maintaining high performance, new copying machines endowed with various value added functions to automate the operations which have been done manually have been developed.
As one of these apparatuses having value added functions, for example, an apparatus which automatically performs a part of filing works that have been done manually up to now, such as collecting sheets discharged from a copying machine or a printer automatically, binding a bundle of these sheets with staples, punching holes in the sheets, and moreover, encasing the copied or printed sheets with a cover and automatically starching them for bookbinding, has been developed. Such an apparatus to perform works on the discharged sheets is called a finisher.
In such a finisher uniting a plurality of functions, however, there is a possibility that all functions are suspended by a functional stop of a part of one function in such a case when the part thereof has, although not having trouble, become impossible to operate. For example, in the case where it has run out of the staple needles, although the bookbinding by a cover binding is still possible, all functions are stopped and, depending on circumstances, even the copying machine or the printer to which the finisher is connected is also made to quit its operation. The same problem happens when the binding cover is used up, and it causes the deterioration of efficiency in using the copying machine.
Such problems are especially remarkable with a multifunctional copying machine. For example, in a copying machine possessed of what is called reserved copying function which is enabled to introduce a plurality of sets of documents in advance and perform each different treatment set by set, when doing a reserved copying operation in such a manner as the first job corresponds to a stapling treatment, the second job to a binding treatment, and the third job to a stapling treatment, the first job stops its execution without staples and, even if the following second job of the binding treatment is feasible, all jobs after the first job will stop their operations.